SB 

•ft 3 



U. S. DEPARTMENT OF AGRICULTURE. 
BUREAU OF PLANT INDUSTRY — BULLETIN NO. 125. 



B. T. GALLOWAY. Chief of Bureau. 



DRY-LAND OLIVE CULTURE IN 
NORTHERN AFRICA. 



BY 



THOMAS H. KEARNEY, 

Physiologist in Charge of Alkali and Drought Resistant 
Plant-Breeding Investigations. 



Issued Apkil 11. 1008. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE 

1908. 



Glass 

Book_ 



^7 



- 



Bui. 1 25, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



Plate I. 




Harvesting Chemlaly Olives in a Dry-Land Orchard at Sfax. 



/ 

U. S. DEPARTMENT OF AGRICULTURE, 
BUREAU OF PLANT INDUSTRY — BULLETIN NO. 125. 

B. T. GALLOWAY, Chief of Bureau. 



DRY-LAND OLIVE CULTURE IN 
NORTHERN AFRICA. 



THOMAS H. KEARNEY, 

Physiologist in Charge of Alkali and Drought Resistant 
Plant-Breeding Investigations. 



Issued April 11, 1908. 




WASHINGTON: 

GOVERNMENT PRINTING . OFFICE, 

1908. 



BUREAU OF PLANT INDUSTRY. 



Pathologist and Physiologist, and Chief of Bureau, Beverly T. Galloway. 
Pathologist and Physiologist, and Assistant Chief of Bureau, Albert F. Woods. 
Laboratory of Plant Pathology, Erwin F. Smith, Pathologist in Charge. 
Investigations of Diseases of Fruits, Merton B. Waite, Pathologist in Charge. 
Laboratory of Forest Pathology, Haven Metcalf, Pathologist in Charge. 
Truck, Crop Diseases and Plant Disease Survey, William A. Orton, Pathologist in Charge. 
Plant Life History Investigations, Walter T. Swingle, Physiologist in Charge. 
Cotton Breeding Investigations, Archibald D. Shamel and Daniel N. Shoemaker, Physiolo- 
gists in Charge. 

Tobacco Investigations, Archibald D. Shamel, Wightman W. Garner, and Ernest H. 

Mathewson, in Charge. 
Com Investigations, Charles P. Hartley, Physiologist in Charge. 

Alkali and Drought Resistant Plant Breeding Investigations, Thomas H. Kearney, Physi- 
ologist in Charge. 

Soil Bacteriology and Water Purification Investigations, Karl F. Kellerman, Physiologist 
in Charge. 

Bionomic Investigations of Tropical and Subtropical Plants, Orator F. Cook, Bionomist in 
Charge. 

Drug and Poisonous Plant Investigations and Tea Culture Investigations, Rodney H. 

True, Physiologist in Charge. 
Physical Laboratory, Lyman J. Briggs, Physicist in Charge. 

Crop Technology and Fiber Plant Investigations, Nathan A. Cobb, Crop Technologist in 
Charge. 

Taxonomic and Range Investigations, Frederick V. Coville, Botanist in Charge. 

Farm Management Investigations, William J. Spillman, Agriculturist in Charge. 

Grain Investigations, Mark A. Carleton, Cerealist in Charge. 

Arlington Experimental Farm, Lee C. Corbett, Horticulturist in Charge. 

Vegetable Testing Gardens, William W. Tracy, sr., Superintendent. 

Sugar-Beet Investigations, Charles O. Townsend, Pathologist in Charge. 

Western Agricultural Extension Investigations, Carl S. Scofield, Agriculturist in Charge. 

Dry-Land Agricultural Investigations, E. Channing Chilcott, Agriculturist in Charge. 

Pomological Collections, Gustavus B. Brackett, Pomologist in Charge. 

Field Investigations in Pomology, William A. Taylor and G. Harold Powell, Pomologists 
in Charge. 

Experimental Gardens and Grounds, Edward M. Byrnes, Superintendent. 

Seed and Plant Introduction, David Fairchild, Agricultural Explorer in Charge. 

Forage Crop Investigations, Charles V. Piper, Agrostologist in Charge. 

Seed Laboratory, Edgar Brown, Botanist in Charge. 

Grain Standardization, John D. Shanahan, Expert in Charge. 

Subtropical Laboratory and Garden, Miami, Fla., Ernst A. Bessey, Pathologist in Charge. 

Plant Introduction Garden, Chico, Cal., August Mayer, Expert in Charge. 

South Texas Garden, Brovmsville, Tex., Edward C. Green, Pomologist in Charge. 

Cotton Culture Farms and Farmers' Cooperative Demonstration Work, Seaman A. Knapp, 

Special Agent in Charge. 
Congressional Seed Distribution (Directed by Chief of Bureau), Lisle Morrison, Assistant 

in General Charge. 



Editor, J. E. Rockwell. 
Chief Clerk, James E. Jones. 



APR 22 1903 
D. otD. 



Alkali and Drought Resistant Plant Breeding Investigations. 



SCIENTIFIC STAFF. 



Thomas H. Kearney, Physiologist in Charge. 



L. L. Harter, Assistant Physiologist. 
125 
2 




LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 

Bureau of Plant Industry, 

Office of the Chief, 
Washington, D. C, January 5, 1908. 

Sir : I have the honor to transmit herewith and to recommend for 
publication as Bulletin !S T o. 125 of the series of this Bureau the ac- 
companying manuscript, entitled " Dry-Land Olive Culture in 
Xorthern Africa.'* 

The culture of the olive without irrigation in a region where the 
average yearly rainfall is only 9.3 inches is the most highly suc- 
cessful example of dry- farming methods applied to a tree crop of 
which we have any knowledge. It has long passed the experimen- 
tal stage, having been carried on in southern Tunis with the methods 
now in use for at least fifty years and having been developed on a 
vastly more extensive scale in the same region during the early cen- 
turies of the Christian era. 

The description here given of the methods and of the type of tree 
adapted to this system of culture will be of special interest to that 
portion of the southwestern United States where olive culture is pos- 
sible. But it also concerns arid and semiarid regions outside of the 
olive zone where arboriculture, based upon other crops, seems des- 
tined to become an important feature in dry-land agriculture. The 
present paper should stimulate the search for useful trees capable of 
being grown profitably under dry-farming conditions. 

In the course of an expedition to Tunis for the Office of Seed and 
Plant Introduction and Distribution, the primary object of which 
was to obtain promising varieties of dates for trial in the south- 
western United States, Mr. Kearney spent several weeks in the dry- 
land olive-growing districts studying the methods used and the 
conditions under which the culture is there carried on. This was 
done at the suggestion of Mr. W. T. Swingle, of this Bureau, who 
has charge of investigations in dry-land arboriculture. 

The drought-resistant variety of the olive that is grown in Tunis 
has been introduced with a view to establishing dry-land olive culture 
in the United States. Investigations along this line will be carried 



4 



LETTER OF TRANSMITTAL. 



on in cooperation between the offices of Plant Life History Investiga- 
tions and of Alkali and Drought Resistant Plant Breeding Investi- 
gations. 

Acknowledgment is here made of the valuable assistance rendered 
Mr. Kearney in the course of his investigations by the Tunisian au- 
thorities and by private individuals interested in olive culture. Men- 
tion should be made of the courtesies extended by M. Fidelle, late 
controleur civil at Sfax; M. Minangoin, inspector of agriculture in 
the Direction of Agriculture and Commerce at Tunis ; Mr. Leonardi. 
British vice-consul at Sfax; M. Robert, president of the chamber of 
commerce at Susa; and MM. Louis Fidelle and A. Chatel, olive 
growers at Sfax. 

The illustrations which accompany this paper are considered 
essential to a full understanding of the text. 
Respectfully, 

B. T. Galloway, 

Chief of Bureau. 

Hon. James Wilson, 

Secretary of Agriculture. 

125 



CONTENTS. 



Introduction 

Importance of dry-land arboriculture in ancient Africa 

Dry-land olive culture in modern Tunis 

General characteristics of the Sfax region 

Climate 

Topography and soils 

Topography and natural vegetation 

Soils 

The olive orchards of Sfax 

The variety grown : 

Propagation 

Clearing the land 

Planting 

Distance between the trees i 

Time and method of planting 

Watering the young trees 

Tillage 

Manuring 

Pruning 

Harvesting 

Yields obtained 

Relation of rainfall to yields 

Labor 

Utilization of the run-off in olive culture in other parts of Tunis. 

Summary 

Description of plates 

Index 



ILLUSTRATIONS. 



PLATES. 

Page. 

Plate I. Harvesting Chemlaly olives in a dry-land orchard at Sfax_Frontispiece. 
II. General view of the older dry-land olive orchards near Sfax 42 

III. A fruit-bearing twig of the Chemlaly olive 42 

IV. Fig. 1. Recently planted dry-land olive orchards near Sfax, show- 

ing the careful alignment and wide spacing of the trees. 
Fig. 2. — The interior of a Sfax olive orchard, showing wide 
planting, clean cultivation, and careful pruning 42 

Text Figures. 

Fig. 1. Map of Tunis, showing the probable extent of the dry-land ar- 
boricultural region in ancient times and the area now occu- 
pied by dry-land olive orchards 9 

2. An olive tree, probably several centuries old, growing without 

irrigation in Algeria 11 

3. Diagram showing construction of cisterns at Sfax 16 

4. Diagram showing method of planting olive truncheons at Sfax__ 23 

5. The " maacha," the tool used by the Arabs in exterminating 

Bermuda grass and other weeds 26 

6. Diagram illustrating a method of conducting surface water to 

the base of an olive tree 27 

7. Sketch showing the proper form to give in pruning a three-year- 

old olive tree 29 

8. The tree shown in figure 7 as pruned when four years old 29 

9. The tree shown in figures 7 and 8 as it appears when five years 

old 30 

10. Chart showing the rainfall and the production of olive oil at 

Sfax from 1895 to 1905 — 33 

125 

6 



B. P. I. — 337. 

DRY-LAND OLIVE CULTURE IN NORTHERN 

AFRICA. 



INTRODUCTION. 

A great awakening to the possibilities of clry-land agriculture has 
recently taken place in the western United States. Land is being rap- 
idly taken up and brought under the plow, largely by eastern farmers, 
in regions where the average yearly rainfall does not exceed 18 inches 
and where water is not available for irrigation. The unusually 
heavy rainfall of the past few seasons has alloAved many of the new- 
comers to obtain good crops of small grain and forage under these 
conditions ; but the recent recruit to " dry farming " must not lose 
sight of the fact that such periods of unusually heavy rainfall are 
sure to be followed sooner or later by periods of drought, when the 
plants ordinarily grown in humid regions will give him but uncer- 
tain results. To insure against disaster he should be on the lookout 
for drought-resisting varieties of the crop plants he is familiar with 
or else for new crop plants adapted to arid conditions. 

No class of plants is more resistant to drought than certain trees 
and shrubs, some of which are extremely useful in countries having 
a climate similar to that of the Great Plains and Great Basin regions 
of the United States. Arboriculture (tree culture) is one of the 
safest and most promising lines along which dry-land agriculture 
can develop. Experience in various parts of the Old World has 
shown that drought-resisting trees will live and will often produce 
a crop in years when no shallow-rooted annual crop will return the 
seed sown. 

The most highly developed and successful example of dry-land 
arboriculture known to the writer is based on the olive, a tree that 
is peculiarly well fitted for growing under arid conditions. Its 
leaves are protected against excessive loss of water by the thick skin 
or cuticle of the upper surface and by the scurf of scale-like hairs 
with which the under side is covered. Its root system is of such a 
nature as to permit it to grow without irrigation in regions where 
the rainfall is scanty and the ground water is practically out of 

125 



8 



DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



reach. The roots of the olive run for long distances comparatively 
close to the surface of the soil, and are thus able to take up the 
moisture that penetrates a few inches into the ground after every 
moderate rainfall. The unusual hardiness of this tree is shown by 
the fact that in many localities in northern Africa where it was once 
planted it has persisted for centuries without receiving any attention, 
often running wild and mingling with the native trees and shrubs on 
the driest hillsides. 

Fifteen hundred years ago southern Tunis was covered with thriv- 
ing olive orchards, but these gradually disappeared after the country 
was conquered by the Arabs, so that at the beginning of the last 
century olive culture had almost died out in that region. A good 
beginning has since been made in reestablishing it, and to-day 
the dry-land orchards of southeastern Tunis are the wonder and 
admiration of olive growers the world over. 

A description of this model arboriculture, of the climatic and 
soil conditions under which it is carried on, and of the methods used 
and the results obtained can hardly fail to interest those who are 
concerned in dry-land agriculture. It is true that in the United 
States the olive can be a profitable crop only in the warmer parts 
of the arid and semiarid districts, i. e., in southern and western 
Texas, in southern Arizona, and in California. But there are other 
drought-resistant trees that are better able to Avithstand cold and can 
therefore be grown to advantage farther north. Some of these, 
although not yet well known in the United States, are of great im- 
portance in various parts of the world, being grown either for their 
fruit, for forage, or for timber and fuel. In the drier parts of 
Europe and Asia there are varieties of our common orchard trees 
that would probably give better results under dry farming conditions 
than the varieties ordinarily grown in the humid parts of the United 
States or under irrigation in the West. An account of dry-land 
olive culture in Tunis should therefore be useful even outside the 
olive zone, as it will direct attention to the type of tree and the 
methods of culture that are likely to give the best results. 

IMPORTANCE OF DRY-LAND ARBORICULTURE IN ANCIENT 

AFRICA. 

Southern Tunis is to-day an arid, treeless waste, almost a desert, 
covered with a sparse growth of thorny bushes and coarse bunch- 
grasses. There are no streams of considerable size to furnish water 
for irrigation, and the average yearly rainfall is small, ranging from 
8 to 14 inches. In many places a fair crop of wheat or barley can 
be expected only once in three or four years. This region is now 
uninhabited, save by a few thousand Bedouins, who wander from 



DRY-LAND ARBORICULTURE IN ANCIENT AFRICA. 



9 




place to place in search of pasturage for their sheep and goats. Ex- 
cept on the coast and at a few points near the mountains along the 
northern and western borders of the district there are no large towns 
and hardly any permanent villages. The desolation is almost every- 
where complete. 

Yet during the third to the seventh century of the Christian era 
this whole dis- 
trict (fig. 1) , from 
the seacoast west- 
ward into what 
is now eastern 
Algeria, was 
thickly d o 1 1 e d 
w i t h thriving 
villages and 
farms. In an 
area not exceed- 
ing 20,000 square 
miles — 15,000 
within the bound- 
aries of modern 
Tunis and per- 
il a p s 5,000 i n 
Algeria — t here 
were at least a 
dozen cities of 
10,000 to 30,000 
inhabitants. A 
network of splen- 
did paved roads, 
such as the Ro- 
mans k n e w s o 
well ho ay t o 



Fig. i. 



Map of Tunis/' showing the probable extent of the 
dry-land arboricultural region in ancient times and the area 
now occupied by dry-land olive orchards. (After Bourde.) 



build, connected 
these cities with 

each other and with those of the seacoast. 

prosperity, that part of the region belonging to what we now 



While in the height of its 
call 



a The northeastern portion of the lightly shaded area, at least near the 
seacoast, is not typical of the dry-land arboricultural region, the yearly rainfall 
at Snsa averaging 16.6 inches. In the southeastern portion (below Gabes) it 
is unlikely that the dry-land orchards extended as far from the coast as is 
indicated on the map. In the absence of exact data for correction, however, it 
seems best to follow the limits of the region as traced by Bonrde (Rapport 
snr les Cultures Fruitieres, etc., Tunis, 1899). 

26017— Bull. 125—08 2 



10 



DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



Tunis, of which it formed about one-third, had a population of at 
least 1,500,000, or about the present population of the whole of Tunis. 

The flourishing state of this part of Africa in former times is 
abundantly attested, not only by the statements of Arab writers who 
saw the country before it had complete^ relapsed into its present 
desolation, but by the ruins that are strewn over it in such numbers 
that one can hardly ride for half a mile without encountering some 
fragment of an ancient building, or cistern, or reservoir. The pub- 
lic buildings of the cities had a degree of architectural merit which 
shows that the ancient inhabitants enjoyed not merely prosperity, 
but wealth and luxury. The inscriptions prove that some of the 
finest of these structures were built not by the government or the 
municipality but by private citizens inspired by local pride, which 
was kept alive by the keen rivalry that existed among the towns of 
Roman Africa. 

We need mention only two examples of the splendid development 
of this country in Roman times. In an area of 100 square miles 
around the ancient city of Suffetula (fig. 1) there have been found 
the remains of 3 cities, 15 towns, and 45 small villages, besides almost 
innumerable scattered farm buildings. Near the seacoast, on the 
site of the ancient city of Thysdrus (fig. 1), stands a great amphi- 
theater which is second in size only to the Colosseum at Rome and is 
estimated to have seated 60,000 people. But the Roman city which 
it adorned has given place to a squalid Arab village huddled under 
the Avails of the amphitheater, while around it in every direction 
stretches a bare, uncultivated plain. How can we account for the 
existence of the 60,000 souls that crowded the amphitheater of Thys- 
drus on festival days to view the sports of the arena ? How did the 
teeming population of Suffetula support itself and accumulate wealth 
sufficient to build the beautiful marble temples and baths and theaters 
that adorned the city in the early centuries of the Christian era? 

All the evidence goes to show that the climate has not changed 
materially and that the rainfall has not diminished since Roman 
times. We have no reason to believe that the country was formerly 
better watered or that agriculture based upon irrigation could ever 
have reached a high development in that part of Africa. The re- 
mains of innumerable cisterns lined with masonry or concrete — more 
than 400 have been counted in one small district near Sfax alone — 
prove that the inhabitants had to depend for domestic purposes upon 
stored rain water. Some of the larger cities had public cisterns of 
gigantic size. Even near the mountains it was necessary to utilize 
every spring and to build long aqueducts to carry water to the cities 
and towns. There could have been little to spare for agricultural 
purposes, except, perhaps, to irrigate the gardens immediately around 
the towns. 

125 



DRY-LAND ARBORICULTURE IN ANCIENT AFRICA. 



11 



The gnarled old olive trees that are found here and there over the 
country (fig. 2), often standing in straight rows just as they were 
planted centuries ago, a and the almost innumerable ruins of oil mills 
answer our questions. The remains of more than a thousand oil mills 
are said to exist in the hundred square miles around Suffetula alone. 
The} 7 were built of stone and were often of imposing size. In many 
places the stone basins in which the fruit was crushed and the per- 
forated stone pil- 
lars that sup- 
ported the bar of 
the press are still 
to be seen. 

If we turn to 
the Koman and 
Arabic historians 
and geographers, 
we find abundant 
evidence that the 
wealth of this 
part of Africa 
was based upon 
dry-land tree cul- 
ture on a vast 
scaled The olive 
was undoubtedly 
the chief source 

„ , . Fig. 2. — An olive tree, probably several centuries old, growing 

01 these riches, without irrigation in Algeria. 

although other 

more or less drought-resistant trees, such as the pistache, fig, and 
almond, doubtless played an important part. It has been calculated 
that the olive orchards of southern Tunis covered 2,500,000 acres when 
the Arabs conquered the country, about 700 A. D. Ancient Rome, 
which consumed an enormous quantity of olive oil, drew its supply 
largely from this region. Under the Caesars the province of Africa, 
which comprised the same territory as modern Tunis, was taxed 
300,000 gallons yearly for the benefit of the capital. So important 

a Olive trees several hundred years old are frequently met with in Algeria and 
Tunis. In many places the existing trees are offshoots that have sprung up 
from the roots of older ones, the original trunk having long since disappeared. 

h This view was first advanced in a convincing form, with an admirable sum- 
ming up of the historical and archaeological evidence, by P. Bourde, at one time 
Director of Agriculture in Tunis, in a little pamphlet entitled " Rapport sur les 
Cultures Fruitieres et en Particulier sur la Culture de 1' Olivier dans le Centre 
de la Tunisie." (Report on Fruit Culture and Especially Olive Culture in Cen- 
tral Tunis.) Tunis, 1802 ; 2d edition, 1899. 

c Graham, Alexander. Roman Africa, London, 1902, p. 57. 
125 




12 



DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



was this article in the ancient commerce of the country that, as the 
local tradition has it, one of the cities near the eastern coast built a 
conduit solely for the purpose of transporting oil to its seaport. 

The Arab invaders, being a pastoral and not an agricultural people, 
are said to have wantonly destroyed the olive orchards in order to 
create pastures for their flocks. More probably the orchards gradu- 
ally died out from neglect, large numbers of the original inhabitants 
of the country having been killed or driven from their farms by the 
invaders, who neither knew nor cared anything about tree culture. 
During the centuries that followed, the country was in too turbulent 
a state to make a restoration of the olive orchards possible. More- 
over, the decline of Rome and the destruction of commerce on the 
Mediterranean put an end to the foreign trade in oil and left Tunis 
without a market for its surplus production. 

However this may be, only mere fragments of this magnificent for- 
est of olives remain to-day in southern Tunis. In the northern part 
of the country, where the rainfall is much greater and the trees can 
exist without the use of special cultural methods to conserve moisture 
in the soil, olive growing has continued without interruption down to 
the present time. 

DRY-LAND OLIVE CULTURE IN MODERN TUNIS. 

At a few points along the coast in central and southern Tunis 
the orchards never disappeared entirely, and within the last century 
a notable effort has been made to reestablish the ancient condition of 
things in the neighborhood of Sfax, a thriving seaport on the eastern 
coast (fig. 1). The work was begun by the inhabitants on their 
own initiative, hesitatingly and inefficiently at first. About 1840 the 
system of planting and of tillage now in use was introduced or 
revived a by one of the more intelligent natives, and from that time 
the progress was rapid. When the French occupied Sfax in 1881 
the orchards already covered 45,000 acres, and up to that time Euro- 
peans had had no part in the work. . 

During the last twenty years most of the new orchards have been 
created by French capitalists, although native laborers have been 
almost exclusively employed and the cultural methods are essentially 
those in use before the. country was occupied by Europeans. Be- 

a In all probability the system of wide spacing of the trees and tborongb till- 
age is not a recent invention, but was in use by tbe Romans more than .1,500 
years ago. These practices, or at least the tradition of them, doubtless con- 
tinued to exist in the region through all the centuries of the Arab domination, 
to be brought once more into general use during the past century. 
125 



DRY-LAND OLIVE CULTURE IN MODERN TUNIS. 



13 



tween 1892 and 1904 French stock companies and individual colonists 
purchased from the Tunisian government 200,000 acres of public land 
and planted more than one and a half million olive trees, besides a 
large number of almonds. These lands are sold by the government 
at the rate of 75 cents an acre, one-half of the price being payable in 
advance and the remainder within four years, on condition that the 
purchaser shall put the land into a tree crop before the end of that 
time. This is in pursuance of the policy of the government to en- 
courage in every possible way the restoration of the olive orchards 
that made the country prosperous in ancient times. 

At present the orchards extend without interruption to an average 
distance of 20 to 25 miles from Sfax, while some of the outlying 
plantations are as much as 40 miles distant from the town. Those 
within a radius of 12 miles from Sfax, which are now in full bearing, 
belong almost exclusively to natives, while beyond them are the 
plantations of young trees more recently established by French col- 
onists. These newer orchards are in nearly all cases very large, 
some of them containing more than 25,000 trees. The entire area 
around Sfax occupied by dry-land olive orchards was estimated in 
J 900 to be 475,000 acres, containing 3,333,000 trees. During the ten 
years from 1896 to 1905 a yearly average of more than 1,000,000 gal- 
lons of oil was produced. The product of these orchards is sufficient 
to maintain about two dozen oil mills in the town of Sfax, operated 
by Europeans and equipped with modern machinery, besides twice 
as many native mills, in which the power is furnished by animals. 

This wide expanse of orchards is a most impressive sight. The 
best view of it (see PI. IV, fig. 1) is to be had from the summit of 
a little hill about 10 miles northwest of Sfax to which all visitors 
are taken. The straight rows of trees, separated by broad bands 
of bare, reddish soil, stretch to the horizon in almost every direc- 
tion. The whole face of the country is striped with gray-green 
and red. Probably nowhere else in the world has olive culture been 
so highly developed. The regularity of the planting is striking to 
anyone who is familiar with the haphazard way in which the trees 
are set out on hillsides in most parts of the Mediterranean region. 
The trees stand in perfectly straight lines and are 65 to 80 feet apart 
in each direction. They are carefully trimmed so as to have a sym- 
metrical, square-topped spread of foliage and are remarkably uni- 

a The jury for olive culture of the Congress held at Tunis in 18SS, which 
was composed largely of French olive growers, agreed that the plantations at 
Sfax are " superb and leave far behind anything to be seen in Europe as to 
development of the trees and quantity of the fruit." At that time the orchards 
were still practically all in the hands of natives. 
125 



14 DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



form in size and shape. Nothing else is grown among them after 
they begin to bear, and the cultivation is so clean that it is hard to 
find a blade of grass in the well-cared- for orchards. 

This admirable culture is carried on without irrigation in a region 
where the rainfall averages only 9.3 inches and sometimes falls as 
low as 6 inches during several successive years. It is the most suc- 
cessful example of dry farming applied to a tree crop of which 
we have any knowledge. 

In order to understand the cultural methods practiced, it is neces- 
sary first of all to know something of the physical conditions of the 
Sfax region. 

GENERAL CHARACTERISTICS OF THE SFAX REGION. 

CLIMATE. 

Sfax, like most localities in northern Africa, has many of the 
climatic peculiarities of the vast Sahara Desert, which practically 
reaches the sea near the border of Tripoli, 110 miles southeast of 
Sfax. For this reason the climate of the east coast of Tunis, even 
as far north as the city of Tunis (fig. 1) is much more desert-like 
than the coast of Algeria, which is separated from the Sahara by 
two ranges of mountains. At Sfax the chief points in which the 
climate approaches that of the desert are the small rainfall and the 
long, hot summers. Yet it is not a typical desert climate, for the 
neighborhood of the sea gives it a comparatively high relative 
humidity and smaller daily and seasonal ranges of temperature 
than those that characterize the Sahara itself. 

Table I shows the average monthly temperatures at Sfax : 



Table I. — Monthly and annual average mean, mean maximum, and mean mini- 
mum temperatures at Sfax. in degrees Fahrenheit. 







Mean 


Mean 


Mdnth. 


Mean. 


of the ' 


of the 






maxima. 


minima. 




°F. 


°F. 


°F. 


January _._ _, _ 


61.8 


59.1 


43.3 


February _ _ _ _ _ .. _. __ . 


54.4 


61.8 


46.9 


March _ . . __ 


59.1 


67.2 


50.2 


April _ _ _ _ _ _ _ _ 


63.2 


72.1 


54.9 


May . _ __ 


68.8 
72.8 


77.5 


60.5 


June ___^____ _ . _ 


80.9 


65.9 


July 


78.5 


87.8 


72.0 


August. _ _ _ ______ 


79.3 


88.1 


72.9 


September. _ ________ _ _ __ 


78.4 


86.6 


73.2 


October _ _ _ 


72.8 


79.4 


64.5 


November-. _ __ _ _ . _ __ _ 


61.8 


69.1 


53.7 


December.. ___ .__ 


54.0 


62.5 


45.8 




Annual mean.. _ .__ . __ _________ 


66.2 


74.3 


58.6 









a The monthly means for Sfax are based upon records covering a period that varies in 
length for different months from eight to seventeen years, but they have been corrected so 
as to agree with the sixteen-year means for each season (winter, spring, summer, and 
autumn) given by G. Ginestous (Etude sur le Climat de la Tunisie, Bui. Dir. Agric. et Com. 
Tunis, 1902 and 1903). The correction in most cases amounts to only about 1° F. and in 
no case exceeds 3°. 

125 



CLIMATE OF THE SFAX KEGION. 



15 



Most localities in the southwestern portion of the United States 
are characterized by a greater range of temperature than occurs at 
Sfax, having colder winters and warmer summers. At Tucson, 
Ariz., the monthly mean temperatures are much like those at Sfax, 
except for May, June, July, and August, when the temperatures are 
considerably higher at Tucson. The means of the maxima of the 
spring and summer months are much higher at Tucson than at Sfax, 
while the means of the minima are much lower at Tucson during the 
nine months from September to May. The yearly mean of the 
maxima is nearly 8 degrees higher, and the yearly mean of the 
minima is 6^ degrees lower at Tucson than at Sfax. 

San Antonio, Tex., corresponds closely with Sfax in the mean tem- 
peratures of all the months, except April, May, and June, when the 
monthly means are considerably higher at San Antonio. The monthly 
means of the maxima are uniformly somewhat higher at San An- 
tonio, the difference being most marked for the months of April to 
July. The monthly means of the minima at San Antonio are slightly 
lower in autumn and winter but somewhat higher in spring and 
summer than at Sfax. 

There is no evidence, however, that within wide limits temperature 
is a factor of very great importance in olive culture. 

Table II shows the average monthly and annual precipitation at 
Sfax : 



Table II. — Average monthly and annual precipitation at Sfax/ 1 



Month. 


Precipi- 
tation. 


Month. 


Precipi- 
tation. 


January __ _ _ _ . _. 


Inches. 
0.97 
1.17 
0.70 
1.25 
0.58 
0.08 
0.04 


August _ - _ _ _ — 


Inches. 
0.04 
0.78 
1.17 
1.21 
1.36 


February.— _ ._ 


September.- _ _ 


March. _ _ 


October _ _ _ 




November _ _ 


May_ _ _ _ 


December _ _ 


June _ _ 


Total annual__. _ 


July 


9.35 







a Based upon a period of fifteen years (1886 to 1900). The above data are taken from 
G. Ginestous, Les Pluies en Tunisie, Dir. Gen. de l'Enseignm. Publ., Serv. Meteorol., ed. 
2, pp.. 86, 87 (1901). 



If we compare the rainfall of Sfax with that of localities in the 
southwestern United States, we find that San Diego and Fresno, 
Cal., Tucson, Ariz., and El Paso, Tex., have practically the same 
yearly total, while at San Antonio, Tex., the yearly total is about 
three times as great, and at St. George, Utah, only about two-thirds 
as great. In the distribution of the rainfall during the different 
months of the year, San Diego and Fresno most nearly resemble 
Sfax, while Tucson, El Paso, and San Antonio show a marked dif- 
ference in their relatively heavy midsummer rainfall. Most of the 
precipitation at Sfax occurs in the autumn, winter, and early spring, 

125 



16 DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



December being the month of greatest rainfall, with a second maxi- 
mum, only slightly lower, in April. July and August are the driest 
months. 

The total rainfall at Sfax varies greatly in different years. Thus, 
in 1890 it amounted to 17.4 inches, and in 1895 it was only 3.2 inches. 
During the seven years from 1898 to 1904 the total rainfall was only 
41 inches; hence the yearly average was only 5.8 inches. The rela- 
tion that apparently exists between the rainfall and the size of the 
olive crop is discussed farther on. 

There are no perennial streams in the Sfax region. The inhabi- 
tants depend upon wells and cisterns for water for irrigating their 
gardens and newly set out olive trees as well as for household pur- 
poses. The wells vary greatly in depth. For instance, about 30 
miles north of the town there is a well 220 feet deep, while only 34 



town and the olive orchards, the roads are bordered by cisterns of 
a peculiar type (fig. 3). A concrete platform, often 40 or 50 feet 
square and about 2 feet high at the edge, slopes from all sides 
toward the center, the opening of which is protected by a con- 
crete cover. Small holes in the sides of the cover allow the water 
that falls upon the platform to enter the cistern beneath. Water is 
drawn when needed through a hole in the top of the cover, which is 
protected by a movable lid. This type of cistern has been used in 
Tunis for two thousand years or more. 

In years of unusually small rainfall, such as 1904, water becomes 
so scarce that 4 or 5 gallons (the capacity of the ordinary water jar 
used by the natives) are retailed for 2 cents. It has been necessary 
at times to import drinking water from Naples and to use sea water 
for washing clothes. 




c 



L_ 



miles away there 
is a 33-foot well. 
The average 
depth is perhaps 
between 50 and 80 
feet. 



Fig. 3. — Diagram showing construction of cisterns at Sfax, being 
a section through two of the openings (o) in the concrete 
cover (/) by means of which water that falls upon the plat- 
form {p) enters the cistern (c) ; s is the surface of the soil. 



In the zone of 
•gardens contain- 
ing a variety of 
fruit trees which 
lies between the 



125 



SOILS OF THE SFAX KEGION. 



17 



TOPOGRAPHY AND SOILS. 
TOPOGRAPHY AND NATURAL VEGETATION. 

The portion of southern Tunis in which dry-land olive culture 
reached its highest development in ancient times is that where 
Quaternary deposits form the surface covering. The district around 
Sfax that is now occupied by olive orchards is a slightly rolling plain 
of low elevation, extending from the coast toward the base of the 
high table-land that occupies central Tunis. In its natural condition 
it is a steppe, in many ways like the great plains east of the Rocky 
Mountains, and especially like parts of western Texas and eastern 
New Mexico. It bears a scattered vegetation, a conspicuous feature 
of which is the Christ thorn (Zizyphus spina- christi) , a spreading 
thorny bush with most of the trunk underground, thus resembling the 
mesquite (Prosopis juliflora) as it grows in eastern New Mexico. 
Like the mesquite, the Christ thorn generally occupies the summits 
of small mounds, which it has probably helped to form by catching 
and holding wind-blown soil. While its stems are usually only 4 or 5 
feet high above ground, its roots are said often to penetrate to a 
depth of 12 feet or more. The presence of this shrub makes the 
clearing of the land difficult and expensive. Sagebrush ( a species of 
Artemisia) and coarse bunch- grass make up the bulk of the natural 
vegetation. 

SOILS. 

The soil that is considered most desirable for olive culture is bright 
red in color. It is generally of considerable depth, but at some places 
within 20 miles of Sfax hardpan is said to be encountered only 24 
inches below the surface. To an average depth of 7 feet the soil 
appears to be generally rather uniform in texture, but below this 
strata of fine material alternate with layers of coarse sand and gravel. 
As regards water content, it is stated a that when the surface soil was 
air dry, at a depth of 8 inches the moisture content was found to be 6 
per cent, at 20 inches 10 per cent, and at 40 inches 14 per cent. This 
would indicate a distribution of soil moisture to which only trees and 
deep-rooted perennials could adapt themselves. It is said & that 
even after several months without rain the soil at a depth of 8 inches 
contains enough moisture to stick together when squeezed in the 
hand. At the end of January, 1905, however, when heavy rains had 
followed a prolonged drought, the writer observed that while the 

a Bourde, P. Rapport sur les Cultures Fruitieres * * * dans le Centre 
de la Tunisie, 2d edition, 1899, pp. 13, 14. 

6 Bertainchand. Note Explicative sur la Carte Agronomique et Hydrologique 
* * * des Terres de la Region de Sfax, Paris, 1896, p. 16. 

26017— Bull. 125—08 3 



18 



DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



first 8 inches of the soil had been thoroughly moistened the next 16 
to 24 inches were very dry and powdery. 

As to texture, this soil when dry has the appearance of a sandy 
loam, with rather coarse particles. An average of the results of 
mechanical analyses by the chemist of the Tunisian government of 
82 samples collected in every part of the Sfax region gives 80 per 
cent of " coarse sand " and 20 per cent of " fine material." Yet 
an apparently typical sample collected by the writer in an olive 
orchard about 5 miles from Sfax was found by the Bureau of 
Soils of the United States Department of Agriculture to contain 
a great deal of silt and clay, amounting together in the surface foot 
to 45 per cent of the whole and in the third foot to 23 per cent. The 
remaining 55 and 77 per cent, respectively, consisted mainly of " fine 
sand " and " very fine sand." The real state of the case appears to 
be that in the natural condition of the soil these fine particles are 
held together by lime or some other cementing material, so as to 
form particles that resemble grains of coarse sand. These become 
separated when the soil is shaken for a long time in water. 6 

Table III shows the results of mechanical analyses made by the 
Bureau of Soils of the United States Department of Agriculture of 
soil samples from the Sfax olive orchards. 



Table III. — Mechanical analyses of soil samples from the olive orchards of Sfax. 



Locality. 


Depth 
taken. 


Fine 
gravel, 
2tol 
mm. 


Coarse 
sand, 

1 to 0.5 
mm. 


Me- 
dium 
sand, 
0.5 to 
0.25 
mm. 


Fine 
sand, 
0.25 to 
0.1 mm. 


Very 
fine 

sand, 

0.1 to 
0.05 

mm. 


Silt, 
0.05 to 
0.005 
mm. 


Clay, 
0.005 to 
mm. 




Inches. 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


P. ct. 


Olive orchard, Sfax 


Oto 12 


0.2 


4.3 


7.1 


24.1 


20.9 


14.1 


30.0 


Do 


13 to 24 


.4 


7.7 


9.7 


33.9 


24.0 


9.1 


16.0 


Do 


25 to 36 


.5 


7.9 


10.3 


34.3 


24.6 


7,1 


15.7 


Do 


Oto 12 


.2 


4.6 


6.8 


26.4 


22.5 


13.4 


26.2 


Olive orchard, 20 miles north 


















of Sfax 


(*) 


.3 


2.7 


3.3 


14.9 


27.0 


22.9 


29.3 



* Adhering to olive truncheons, probably about 12 inches. 



Chemical analyses of a large number of samples of the Sfax olive 
soils by the chemist of the Tunisian government show them to be very 
rich in lime (calcium carbonate), of which there is an average of 
from 5 to 10 per cent. The potash content is also good, the average 
being 0.1 to 0.2 per cent. On the other hand, they are rather poor in 
nitrogen (0.03 to 0.05 per cent) and in phosphoric acid (0.04 to 0.05 

a Bertaincliand, 1. c. 

6 In the French method of mechanical analysis of soils, much less water is 
used and the digestion is much more rapid than in the method followed by the 
Bureau of Soils; consequently by the former method the aggregates of fine 
particles are less likely to be broken up through the solution of the cementing 
material. 
125 



OLIVE ORCHARDS OF SFAX. 



19 



per cent) . According to Trabut," a high lime content is a very favor- 
able factor in growing olives for oil production, as olives produced 
in limestone regions are richer in oil and the oil is of better quality 
than where the soils are deficient in this component. It should be 
noted that while the nitrogen and phosphoric acid content of the 
Sfax soils would be considered low for most crops, the high yields 
and good quality of the oil produced at Sfax are sufficient evidence 
that the supply of these two elements of plant food must be amply 
sufficient for the requirements of the olive. This can perhaps be 
explained by the fact that the roots of this tree occupy so great an 
area of soil (one-seventh to one-tenth acre) that while the percentage 
of these elements to weight of soil is everywhere low the total amount 
available to the roots is actually rather high. 

THE OLIVE ORCHARDS OF SFAX. 

THE VARIETY GROW T N. 

The Sfax orchards contain only one oil-producing variety, the 
Chemlaly, 6 to which probably at least 95 per cent of the trees belong, 
the rest being varieties with larger fruits used for pickling. The 
fruits of the Chemlaly are very small but are produced in great quan- 
tity (Plate III). They are exceedingly rich in oil, yielding 30 per 
cent in factories where modern presses are used and as high as 34 J 
per cent in extraction experiments made by the chemist of the Tunis 
government. These are unusually high percentages, but they are at- 
tributable, perhaps, more to the heat of the climate than to a pecu- 
liarity of the Chemlaly variety, for still farther south in Tunis the 
olives are even richer in oil. In the extraction experiments above re- 
ferred to, olives grown in the celebrated oil-producing district of Bari 
in southern Italy yielded only 28.2 per cent. In European countries 
near the northern limit of olive production the fruit is said to yield 
only 13 per cent of oil. 

Oil made from the Chemlaly variety is very pure and of excellent 
flavor. For commercial purposes, however, it has a serious defect in 
its high content of stearin, or fixed acid, which causes it to congeal 
at relatively high temperatures. This characteristic renders Sfax 
oils difficult to sell in northern Europe, and it is especially prejudicial 
to their use in preserving sardines, etc. It is not, however, an insuper- 
able objection, since the excess of stearin can be removed at a rela- 
tively small expense. 

aTrabut, L. L'Olivier, Bui. 21, Service Bot., Gouvernm. Gen. Algerie, 1900, 
p. 43. 

b Five or six very different varieties, all known as Chemlaly, occur in Tunis. 
That grown at Sfax is commonly designated as the " Chemlali de Sfax." 
125 



20 DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 

Opinions differ as to whether the high stearin content of the Sfax 
olive oils is a peculiarity of the Chemlaly variety or is due to the 
character of the soils of Sfax. That it is not attributable to the 
climate seems certain, for oils made from olives grown in still hotter 
and drier parts of Tunis are said not to congeal more readily than 
do those from the northern part of the country. M. Bertainchand, 
the chief chemist of the Tunis government, holds the character of 
the soil to be responsible, the soils in which olives are grown in 
northern Tunis being generally heavier than those of Sfax. It should 
be noted, however, that oils produced in the oases on the northern 
edge of the Sahara, where the soils are sandier than at Sfax, resemble 
the oils of northern Tunis rather than those of Sfax in their per- 
centages of fluid and fixed acids. Perhaps the low water content 
of the soil contributes to this peculiarity in the composition of Sfax 
oils, northern Tunis having a much higher rainfall and the oases 
being abundantly irrigated. The latest authority who has investi- 
gated this subject holds, however, that the percentage of stearin is 
essentially a characteristic of the variety rather than a direct result 
of the physical conditions.* 

Whether the large yields of fruit obtained at Sfax from the 
Chemlaly olive are an inherent characteristic of the variety or are 
due to the climate or the soil or the superior cultural methods used 
seems not to be known. All authorities agree, however, that 
this variety is exceptionally well adapted to growing without irri- 
gation in a hot, dry climate. It has been suggested by Dr. L. Trabut, 
government botanist of Algeria, that the Chemlaly will probably 
be useful as a drought-resistant stock upon which to graft larger 
fruited varieties. It is, in fact, thus employed to some extent at 
Sfax, but its value for this purpose will probably be limited, since 
olives that are large enough to be commercially valuable for pick- 
ling can in all likelihood be produced only where abundant water 
is available. 

PROPAGATION. 

The Chemlaly olive is never grafted at Sfax but is grown on its 
own roots. It is always propagated by means of large truncheons — 
pieces of wood taken from the base of the trunk or of the largest 
roots — a method that seems to be peculiar to Tunis. 6 These cuttings 

a See Marcille, in Bui. Dir. Agric. et Com., Tunis, 1906, p. 516. 

6 Dr. L. Trabut, the government botanist of Algeria, states that it is not 
practiced in Algeria. Prof. S. C. Mason, arboriculturist of the Bureau of Plant 
Industry, reports that the Cottonwood (Populus deltoides) is sometimes propa- 
gated in western Kansas by means of " snags," or truncheons, pieces of wood 
with several buds obtained by cutting up the branches of this tree. They are 
of the thickness of a piece of stove wood and 1 or 2 feet long. They are some- 
times set in deep furrows and the soil is then firmed in around them. 
125 



CLEARING THE LAND FOR AN ORCHARD. 



21 



are obtained from the old neglected trees — relics of the ancient olive 
orchards — that are scattered over the country (see fig. 2). When such 
trees do not occur on the estate that is to be planted, the cuttings are 
purchased from natives who have them. Either the whole tree is 
uprooted and all the cuttings it can furnish are removed at once with 
a saw or else only two or three are taken off at a time. In the latter 
case the usual method is to cut with a hatchet about half way through 
the root that is selected to furnish the cutting, at two points 8 to 10 
inches apart. A spade is then struck into the upper cleft and the 
root is split down the middle as far as the lower cleft, thus leaving 
unhurt the under half of the root from which the cutting has been 
removed. The wounds are carefully trimmed with a pruning knife. 
In this way the root which furnishes the cutting is left attached to 
the parent tree and continues its functions. 

The truncheons thus obtained are generally 8 to 10 inches long and 
of very unequal thickness, although said to average 4 inches. The 
drier the weather and the soil at the time of planting the larger they 
should be. In no case should they weigh less than 2^ pounds, and 
they are generally heavier, for the vigor of the tree for the first year 
or two, at least, depends largely upon the size of the truncheon from 
which it originates. They retain the bark and should have at least 
three eyes or buds. If they have roots attached, these are cut off and 
care is also taken to trim away all rotten wood. The best results 
are obtained with cuttings taken below the surface of the ground. 
When of the dimensions just described they will not be injured by 
exposure for two weeks to the sun and air, but if a longer interval 
elapses before they are planted they should be wrapped in straw or 
else buried in the ground until wanted. 

CLEARING THE LAND. 

The first step in establishing an olive orchard at Sfax is, of course, 
clearing the land of its native growth of -grass and bushes. Where 
the deep-rooted thorny shrub known as Christ thorn occurs this is 

a Four dozen such cuttings were imported from Sfax by the Department of 
Agriculture in 1905. They were taken from the trees about February 15 and 
were covered with soil until the end of the month, when they were packed with 
wet straw in ventilated wooden boxes and shipped to New Lork, being watered 
at least once during the voyage. When unpacked at Washington on April 20, 
only one or two of them showed signs of life. When planted, however, hardly 
one failed to send up numerous shoots, which by October 15 had reached a 
height of 4 to 5 feet. They were sent to San Antonio, Tex., Tucson and Phoe- 
nix, Ariz., and several localities in California. In most cases they have made 
a good growth, and material for further experiments with this variety seems to 
be assured. 
125 



22 



DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



a troublesome and expensive operation, but otherwise a fairly deep 
plowing is generally effective. As a rule, the greatest difficulty in 
getting the land clean and keeping it so is due to the presence of 
Bermuda grass, the worst weed of the Sfax region. As irrigation is 
not practiced, except that the young trees are watered by hand during 
the first one or two summers after planting, it is not necessary to level 
the land. In the largest plantations it is the custom not to clear the 
entire surface before planting but merely strips about 12 feet wide, 
in the centers of which the rows of trees are to be set. These strips 
are broadened from year to year until the whole surface of the 
orchard has been freed from weeds and brush. Whenever possible, 
however, it is preferable to clear the entire area at the outset, since 
the unreclaimed portion harbors Bermuda grass, which rapidly 
spreads into the strips containing the rows of trees. 

PLANTING. 
DISTANCE BETWEEN THE TREES. 

Wide planting, combined with clean cultivation (see Pis. II 
and IV) , is the chief factor of success in olive culture at Sfax. 
Fifty years ago the Arabs hit upon the plan of setting out the trees 
about 80 feet apart each way, thus giving slightly less than seven 
trees to the acre ; but this small number is said to produce as much 
oil as do 50 trees at Susa or 60 to 80 trees in northern Tunis. The 
natives continue to plant at this distance, but there is a tendency 
among the French owners of orchards to decrease the distance be- 
tween the trees to 65.5 feet, which gives space for 10 trees to the acre 
if planted in squares and 11^ trees if planted in quincunx, as is now 
frequently done by French olive growers. This system of wide 
planting conforms to the habit of the olive tree, at least when grown 
under the climatic and soil conditions of Sfax. It is there a com- 
paratively shallow-rooting tree, a but the roots form a dense network 
extending horizontally to an average distance, it is said, of 25 feet in 
every direction. The root systems of two olive trees at Sfax 80 feet 
apart have been observed to meet. 

Great care is taken, even by the natives, to secure a perfect align- 
ment of the trees and to plant them at exactly equal distances. Con- 
sequently the Sfax orchards are models of systematic planting. 

a One olive grower at Sfax informed the writer that practically the entire 
root system is contained in the first 3 feet of the soil. The shallow-rooting 
habit of the olive at Sfax may be at least partly due to the method of propaga- 
tion by truncheons, which prevents the formation of a taproot. Rooted cut- 
tings, such as are used in other parts of Tunis, are said to quickly develop a 
taproot. There is little doubt, however, that the olive is more shallow rooting 
than most fruit trees. 
125 



PLANTING OLIVE TREES. 



23 



TIME AND METHOD OP PLANTING. 

The trees are set out from November to February, but the best 
months are November and December, the benefit of the winter rains 
being thus secured. When heavy rains occur immediately after 
planting, as many as 98 per cent of the trees sometimes live, but 
ordinarily only 80 per cent survive. If the truncheons are set out in 
November, the shoots appear the following spring. If planting is 
deferred until February, the shoots do not ordinarily appear until 
the following autumn 2 or even the second spring, and the percentage 
of trees that fail to grow is often very large. 

The truncheons are always planted at the bottom of holes (see 
fig. 4), these being generally 2 feet square and 2 — or sometimes 2i — 
feet deep. The young shoots are thus partially shaded, and the soil 
around them can be kept much more moist than if the truncheons were 
planted near the surface of the ground. It is advisable to prepare the 
holes several months be- 
fore planting, in order 
that the soil at the bottom 
may become thoroughly 
aerated and be moistened 
by the first autumn rains. 
For November planting it 
is recommended that the 
holes be made in June or 
July, since at that time the 
soil is still moist from the 
spring rains and hence easy 
to work. In a light soil a 
native laborer can dig these PlG 4 ._ Diagram showing method of planting olive 

holes at the rate of fifty a truncheons at Sfax. (After Minangoin.) 

day. 

In planting, the hole is about half filled with loose soil. The 
truncheon is laid on this, the side on which the bark remains and 
which contains the buds being of course uppermost. It is then 
pressed down and covered with about 2 inches of soil. Manure is 
never put into the hole. As the shoots push up, the hole is filled 
until, two or three years after planting, it is nearly level with the 
surface ; but it is desirable to maintain a slight depression, in order to 
hold as much water as possible around the young tree. 

Of the numerous shoots that spring up from the truncheons, all 
are preserved the first year, but during the second year all but the 
two most vigorous ones are removed, and during the third year only 
the best and strongest shoot is allowed to grow. 

125 




24 DRY-LAND OLIVE CULTURE 1 1ST NORTHERN AFRICA. 

Occasionally the truncheons are planted in nursery form before 
being set out in the orchard. In a large orchard thus established 
near Sfax that was visited by the writer, the trees, after having 
grown one year in the nursery and three years in the orchard, were 
5 to 6 feet high above ground. Ordinarily, olive trees grown from 
these large pieces of old wood begin to bear when six years of age, 
but do not give any considerable amount of fruit until ten years old. 

The estimated cost of planting one hundred trees in the manner 
above described is $4.75 to $5.30, including the purchase and trans- 
portation of the cuttings, digging the holes, and planting. This is 
only possible because of the very cheap labor obtainable in Tunis, 40 
to 50 cents being the ordinary day's wages of laborers in the olive 
orchards at Sfax. 

WATERING THE YOUNG TREES. 

While the olive orchards at Sfax are not irrigated after they are 
once established, sufficient water for that purpose being unobtainable, 
it is usually necessary to water the young trees during the first sum- 
mer or two after they are set out. For this purpose the water of wells 
and cisterns is used. There seems to be much diversity of opinion as 
to the number of waterings that are necessary, but the usual practice 
appears to be to water two or three times during each of the first two 
summers after planting, at the rate of 5 to 10 gallons to the tree at 
each watering. Frequently the young orchards are given no water 
during the second summer. In one plantation visited by the writer 
the trees were watered only once after planting. It is said that in 
exceptionally rainy years no watering whatever is necessary and that 
the trees planted in such years make the best growth. The labor re- 
quired in watering is a considerable item in the expense of establish- 
ing an olive orchard at Sfax, the nearest well being often a mile 
distant from some of the trees. The natives water their trees by 
means of earthenware jars holding 4 or 5 gallons, but on the large 
plantations owned by Europeans a watering cart is generally used. 
To facilitate its passage, a strip of land 6 feet or so wide on either 
side of the rows of trees is left unplowed during the summer. 6 

a Minangoin estimates that there should be one well to every 570 acres of 
orchard. (L'Olivier en Tunisie, 1901, p. 57.) 

6 As a means of avoiding at least part of this laborious watering, it was sug- 
gested to the writer by M. Louis Drappier, of the Service des Antiquites et des 
Beaux Arts at Tunis, that a practice followed by the Arabs in establishing 
orchards in parts of Algeria where water is scarce might be advantageously 
adapted to dry-land olive culture. This consists in placing in the bottom of 
each hole in which a young tree is to be set about 100 pounds of cactus pads 
and covering them with a thin layer of soil, upon which the young tree is 
set. It is said that a supply of moisture sufficient to last two years is thereby 
assured. It would seem doubtful, however, whether an adequate supply of 
moisture would thus be provided and also whether good conditions for the roots 
of the young trees would result from this manner of planting. 

125 



TILLAGE OF OLIVE ORCHARDS. 



25 



TILLAGE. 

Good tillage is essential to successful dry-land olive culture as 
practiced at Sfax, and this was thoroughly appreciated from the be- 
ginning by the intelligent natives who brought the present system 
into general use once more. In order to keep as much moisture as 
possible in the soil, a dust mulch, which reduces evaporation to a 
minimum, is maintained on the surface, especially during the sum- 
mer. This loose condition also facilitates absorption of the rain that 
falls in autumn, winter, and spring. Furthermore, the greatest care 
is taken to destroy all weeds that appear. Bermuda grass is the most 
troublesome of these, much of the land suitable for olive culture 
around Sfax being thoroughly infested with it. As it is advisable 
to extirpate this weed before the trees are set out, the best results can 
sometimes be had when planting is postponed until the second year 
after work on the orchard is begun. The following method is recom- 
mended by Minangoin for getting rid of Bermuda grass. 

A shallow plowing — to a depth of only 3 or 4 inches — is given 
With the rude Arab plow, followed by a harrowing, or preferably 
two cross harrowings. In this way the soil is pulverized and the 
grass roots are turned up and exposed to the sun and air. On the 
other hand, a deeper plowing would only bury the rootstocks out of 
reach of the teeth of the harrow and the shoots would quickly find 
their way to the surface again. The land is then gone over with a 
rake — generally the primitive Arab instrument known as the " mes- 
saba " — and the rootstocks gathered up by it are burned. A second, 
somewhat deeper plowing, followed again by the harrow and the 
rake, is said to be in most cases effective in extirpating the grass. 

A different plan requiring much more time and labor, although 
equally effective, is generally followed by the Arabs. Instead of the 
plow they use the " maacha " (see fig. 5), an instrument made like 
a plow, but having in place of a share a flat, thin bar about feet 
long, set so that its front edge slants toward the ground and adjust- 
able so as to cut the soil at the desired depth. It otherwise resembles 
the native plow and is guided in the same way. This implement is 
passed over the land at intervals of a week or two, especially in sum- 
mer, but also a few days after every rainfall in winter and spring. 
The maacha does not remove the roots but is set so as to cut off the 
grass stems an inch or so below the surface of the soil. As a result 
the roots, deprived of leaves, finally rot in the ground. It is some- 
times necessary to use the maacha a dozen times in rapid succession 
before the land is clean. The instrument as used by the natives 
requires a great deal of strength to operate. The driver must stoop 
and throw the whole weight of his body against the handle bar ; but 

125 



20 



DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



an improved form devised by a French colonist at Sfax can be guided 
by a man standing erect with his hands on the bar. 

The importance attached to getting the land clean is shown by the 
fact that the " nrrharci " contract (see p. 34) is not considered to 
have terminated until the Bermuda grass has been extirpated. The 
extraordinary precautions taken to get rid of this weed show how 
essential clean culture is considered. 

After the land has been cleared of weeds, it is worked less often. 
To obtain the best results, however, it is necessary to plow at least 
three times every year, irrespective of the age of the trees. The Arab 
plow, set to a depth of about 4 inches, is generally used. One 
authority recommends that the first plowing be given in the winter, 
immediately after the harvest, in order to loosen the soil that has 



sidered advisable, however, not to plow deeper than 10 inches, to avoid 
injury to the roots of the trees. In addition, the maacha is passed 
over the land, especially after a rain in winter, as often as is neces- 
sary to keep down the weeds and restore the mulch. At least three 
cultivations a year with the maacha are considered essential. The 
natives as a rule do all their cultivating with the maacha, using the 
plow only in preparing the land for seeding to grain. 

It is customary during the winter to keep around each tree a shal- 
low basin of the depth reached by the Arab plow. This is at first 
simply the nearly filled up hole in which the tree was planted, but is 
extended as the tree increases in size, so as to be always a little greater 
in diameter than its spread of foliage. 

In summer the ground is cultivated up to the bases of the trees, but 
each autumn the surface of the basins is j:>acked down and made 
smooth, so as to facilitate gathering the fruit that drops to the ground 




been trampled down in the proc- 
esses of harvesting and prun- 
ing. The second plowing should 
take place in spring, after the 
trees have blossomed, and the 
third in August or September. 
Maity growers, however, omit 
the plowing in summer, and on 
some large plantations only a 
single plowing is given, soon 
after the harvest is finished. A 
marked benefit results if the 



Fig. 5.— The "maaclia," the tool used by the Arabs soil is stirred to a greater depth 




with a French plow once every 



two or three vears. It is con- 



125 



TILLAGE OF OLIVE ORCHARDS. 



27 



during the harvest, which would be hard to pick up from plowed 
ground. The basins also serve the important purpose of catching 
and holding rain water around the bases of the trees during the win- 
ter and spring. In one plantation visited by the writer there were 
two short, shallow trenches, converging in V-shape, as shown in figure 
6, on the uphill side of each tree, which serve to conduct the surface 
water after rains to the basin around the tree. 

The suggestion was made to the writer by a French tenant on one 
of the new olive orchards near Sfax that the rain which falls upon 
the surface of the orchard could be better utilized if only'an area 
around each tree corresponding in extent to that occupied by its 
roots were cultivated, leaving a strip of smooth, unplowed ground 
between each two neighboring trees. The water falling on the lat- 
ter would run off the hard ground between into the cultivated areas 
around the trees. As a result of the existing practice of keeping the 
entire surface of the orchard cultivated, all the water is absorbed 
where it falls, and in the middle of the spaces 
between the trees, at least while the latter are 
young, sinks into the ground without reaching 
their roots. After the trees have reached their 
full growth, however, it is probable that their 
root systems occupy practically the entire area 
of the orchard. 

Until the olive trees begin to bear a consider- 
able quantity of fruit, i. e., usually until they 
are about ten vears old, field crops are fre- FlG - 6.— Diagram nius- 

7 x trating" a method of 

quently grown among them, but after that time, conducting surface 
and sometimes after the sixth year, all such ter ^to ttie base of 

crops are rigorously excluded. Barley is the 

crop that is most often grown in the young orchards, although wheat 
and horse beans ( Vicia faba) are also grown. All these are fall- 
sown crops. Wheat is a more uncertain crop than barley at Sfax 
and is thought by the natives to draw more heavily on the scanty 
supply of moisture in the soil. Even barley, though sown every 
year, can be counted upon to give a good crop only once in three 
years. In some orchards barley and horse beans are grown in 
rotation. % 
From the outset, however, strips of ground 10 to 12 feet wide, in 
the center of which are the rows of trees, are left absolutely bare. 
These are widened and the area devoted to small crops is propor- 
tionately diminished each year until the olives begin to bear, when 
the land is left entirely to the trees. 

a The same practice obtains also in western Algeria. See Trabut, L., L'Olivier, 
Bui. 21, Serv. Bot. Gouvernm. Gen. de l'Algerie, 1900, p. 41. 
125 




28 



DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



MANURING. 

Chemical fertilizers are not used at Sfax, and even the application 
of barnyard manure is rather the exception than the rule, although 
it is admitted that a marked increase of yield can be obtained by this 
means. Domestic animals are few in the Sfax region, and in the 
extensive orchards recently planted by the French on the edge 
of the olive-growing district manure is often almost unobtainable. 
Some of the richer natives who own the older orchards near the town 
are better situated in this respect. 

The first application of manure is said to be generally given when 
the trees are 10 to 12 years old, and thereafter is repeated every four 
or five years at the rate of 100 to 200 pounds to the tree. The manure 
is buried near the foot of the tree, the following method of putting it 
in being recommended by the manager of one of the large French 
plantations : A trench about 6 feet long, 2 feet wide, and 2 feet deep 
is dug on the uphill side of the tree, about 6 feet distant from its 
base, and is filled with well-rotted mixed barnyard manure. For- 
merly the manure was buried around the tree at its very foot, a prac- 
tice that frequently injured the bark of the crown. 

PRUNING. a 

One can not visit the older olive orchards around Sfax without 
being impressed by the symmetry of the trees and the uniformity in 
size and shape of their tops. This regularity is due to the great 
care that is given to the matter of pruning. Certain of the natives 
who are adepts at this work and can prune on an average eight or ten 
trees a day receive 60 cents a day for their services. The cost of 
pruning is partly and sometimes fully covered by the value of the 
wood removed in the process, firewood being scarce and dear in that 
region. The larger branches are removed with a saw and the smaller 
ones with a pruning hook, care being taken to make clean sections. 

From the time the trees are three years old until they begin to 
bear they are trimmed a little every year, just enough to give them 
the proper shape. Severe pruning of the young trees is avoided, as 
it interferes with the proper development of the root s}^stem, upon 
which so much depends in the dry climate of Sfax. During the 
first two or three years it is considered inadvisable to prune the root 
shoot that has been selected to form the trunk, as otherwise it will 
grow up rapidly into a spindling, little-branched stem. When the tree 
is three years old the terminal shoot is cut off, and the first four 

a Much of the information contained in this section is taken from Minangoin, 
N., L'Olivier en Tunisie, Tunis, 1901, a publication that has been freely 
consulted in preparing the chapters on cultural methods. 
125 



PRUNING OLIVE TREES. 



29 




.3^ 



showim 



the 



Fig. 7. — Sketch 

proper form to give in pruning 
a three-year-old olive tree. 
The dotted lines indicate the 
branches that are removed. 
(After Minangoin.) 



branches below it are allowed to develop, all branches farther down 
the stem being suppressed (fig. 7) . It is said that bearing commences 
on an average two years earlier when the terminal shoot is removed 
than when it is allowed to remain. The 
removal of the apex of the stem causes 
the four branches that are left just below 
it to ascend obliquely instead of spread- 
ing horizontally. The year following 
the tips of these four branches are in 
turn removed and all but one of their 
lateral twigs are cut back (fig. 8) . Dur- 
ing the fifth year new twigs begin to 
shoot out from the buds on the stumps 
(fig. 9) and the young tree begins to 
assume definite form. 

The pruning is directed so as to secure 
a symmetrical, well-rounded top (PL 
I and PI. IV, fig. 2) with the leading 
branches at regular intervals and rather 
far apart. Care is taken to prevent the 
tree from becoming so tall as to make 

harvesting difficult, the ideal being a height that equals the spread of 
the foliage. The inner branches are kept well thinned out, so as to in- 
sure the access of as much light as 
possible to all the fruit-bearing 
twigs. The rapidly growing erect 
shoots, which absorb much of the 
sap of the tree and bear little or no 
fruit, are removed, except those that 
are destined to become the main 
branches. Branches growing in a 
horizontal direction or inclined to 
droop at the end are favored. The 
yield largely depends upon the 
attention given to these points. The 
superiority in size of trees and the 
greater magnitude and regularity of 
yield shown by the Sfax orchards as 
compared with those of other parts 
of Tunis are largely attributed to the 
care with which the pruning is done. 
When the trees begin to bear, biennial pruning is generally sub- 
stituted for annual, and the operation is usually performed imme- 
diately after the harvest, in January or February. On some plan- 

125 




Fig. 8. — The tree shown in figure 7 as 
pruned when four years old. (After 
Minangoin.) 



30 



DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



tations, however, the trees are pruned lightly every year, and this is 
said to insure larger yields year in and year out and to cause less 
injury to the trees. In annual pruning, the custom is to prune 
lightly after a small crop in order to secure a heavy crop the season 
following. After a good crop a thorough pruning is given, as the 
same tree will not yield heavily two years in succession. 

HARVESTING. 

Olives commence to ripen at Sfax in October, those borne by the 
youngest trees being the first to mature. The harvest ordinarily 

begins in the latter part of 
October and lasts until the 
end of January, but when 
the crop is unusually heavy 
it sometimes continues until 
March or even April. The 
fruit is mostly sold on the 
tree, the buyer taking charge 
of the harvest. In this, as 
in all operations connected 
with olive growing, greater 
care is taken at Sfax than 
i n m ost olive - producing 
regions. The harvester by 
means of a double ladder 
(see PI. I, frontispiece) is 
able to gather most of the 

Fig. 9.— The tree shown in figures 7 and 8 as f m i t by hand. The USe of 
it appears when five years old. (After . -it p 

Minangoin.) a pole is avoided as iar as 

possible, since the olives are 
likely to be injured by bruises when knocked off. Moreover, many of 
the young twigs, which are to bear the crop of the following year, 
are destroyed when this method is followed. In pruning, the im- 
portance of making every part of the tree as accessible as possible to 
the harvester with his ladder is taken into consideration. 

The natives are very dexterous in gathering the fruit, holding the 
branch with the left hand and stripping it with the right, three fin- 
gers of which are armed with the tips of rams' horns, worn like thim- 
bles. The fruit is stripped off into a basket which is fastened to the 
ladder. When full, the basket is lowered to the ground by means of a 
cord. It is then emptied by the women upon pieces of cloth or mat- 
ting, and the fruit is freed from the debris of leaves, twigs, etc., 
mixed with it. Finally the olives are packed into large panniers, two 
of which make up a camel load (450 pounds). In the evening or 

125 




YIELDS OF OLIVES OBTAINED. 



31 



very early in the morning these baskets are loaded upon camels and 
are thus transported to the factory. When received there they are 
placed in shallow cement tanks without covers and are left exposed 
to the weather for three or four days. This renders them soft and 
permits the extraction of the oil with much less pressure than is 
required when freshly gathered fruit is put into the presses. 

The olives are sold both in the orchard and at the factory at so 
much the " kaffiz," an Arab measure containing about 136 gallons. 
The ordinary price paid per kaffiz at the factory is $13 to $15, which 
is an advance of 10 to 20 per cent on that paid for fruit on the tree. 
The price of a kaffiz of olives varies as much as $4 during a single 
season. In 1899 it rose to $20, and even $22, at the factory. 

YIELDS OBTAINED. 

The rapidity with which the orchards come into bearing depends 
largely upon the thoroughness of the cultivation given them and the 
degree of skill used in pruning. While well-tended trees sometimes 
bear a little when only 3 years old, neglected trees do not begin to 
yield until they are 12 or 15 years old. As a rule it is eight to ten 
years from the time of planting before any considerable quantity of 
fruit is produced. Well cared for trees that are 10 years old are con- 
sidered to be worth $3 to $3.50, the value increasing to from $5.70 to 
$7.60 for trees 15 years old and from $9.50 to $13.30 for trees 25 years 
old. When they reach the age of 25 years the trees are generally in 
full bearing. According to one authority, however, the yields con- 
tinue to increase up to the agre of 40 years. Minano-oin a gives the 
quantities of fruit and of oil from trees of different ages as follows : 



Table IV. — Average yields of fruit and of oil from olive trees of different ages 

in the orchards of Sfax. 



Age of tree. 


Tield of 
fruit. 


Yield of oil. 


Percentage 
of weight 
of fruit. 


Absolute 
quantity. 


Tears: 

8_ _ - 


Gallons. 
5.3 
10.6 
15.9 


Per cent. 
15 
15 
20 
25 


Gallons. 

0.8 
1.6 
3.2 
5.3 


10 


15 — - — — - - - 


20 — - 


21.2 



It is evident from the data given in Table IV that not only the 
total yields of fruit and oil but the percentage of oil to fruit by 



a Minangoin, N. Culture de l'Olivier * * * clans le Centre de la Tunisie, 

Tunis, 1900, p. 16. In the original the quantities are of course given in liters, 
not gallons. 
125 



32 



DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



weight increase rapidly with the age of the tree. When 25 years 
old, the average yield of oil per tree is about 6 gallons. Some 
individual trees attain a production of over 50 gallons of fruit, 
but such heavy bearers are said to constitute not more than 1 or 2 
per cent of the Sfax orchards. 

After the trees have come into full bearing their yields are said 
to remain stationary until they are 50 years old, when their pro- 
ductiveness begins to decline. When 80 years old the yields are said 
to diminish and become very irregular, dwindling to almost nothing 
in trees a hundred 3 r ears old. If thoroughly pruned, cultivated 
deeply enough to lay bare the roots, and well manured, however, old 
trees can again be brought into bearing. 

The crop at Sfax from trees over 20 years old is said to be worth 
on an average about $2, although sometimes attaining from $3 to $4 
per tree. It must be remembered, however, that there are only seven 
to ten trees to the acre. 

It is instructive to compare the yields given in Table IY with 
those obtained in other olive-growing countries. Thus, in Provence, 
in southern France, well cared for trees in full bearing are said to 
produce an average of only 3.9 to 5.3 gallons of fruit, which, if 
we take the percentage of oil to be about half what it is at Sfax, 
would give about 0.6 gallon of oil. Hence, although in Provence 
the trees are planted only 33 feet apart, which allows about 60 to the 
acre when in squares and 70 when in quincunx, the yield of oil to the 
acre from well-tended orchards would still fall short of that at Sfax. 

The olive is markedly periodic in its bearing and will not produce 
two heavy crops in succession, no matter how favorable the climatic 
conditions may be. At Sfax the rule is said to be that if a tree 
yields heavily one season it will give a medium crop the second and 
a light crop the third season following. Different trees yield heavily 
in different years, so that every year some trees are giving their 
maximum crop. 

In January, 1900, there were in operation at Sfax 28 oil mills 
operated by steam power and 48 native mills operated by animal 
power. There were 15 mills controlled by Europeans and equipped 
with modern machinery. The total number of presses was 155, of 
which 56 were run by steam and 99 by animal traction. 

RELATION OF RAINFALL TO YIELDS. 

It is interesting to compare the amount of rainfall with the char- 
acter of the olive crop at Sfax during each of a series of years, such 
a comparison being given in Table V and being shown also in 
figure 10. 

125 



KELATIOIST OF RAINFALL TO YIELD OF OLIVES. 



33 



Table V. — Yearly rainfall and olive production at Sfax in the years 1895 to 
190//, inclusive, the latter being indicated hy the exports of olive oil from the 
port of Sfax during each following year. 



-tear. 


Total 
rainfall. 


Olive crop of the year. 


Quantity. 

- 


Proportion, 
of the 
average 
yield. 


1895 


Inches. 
3.18 
10.53 
12.92 
6.75 
5.57 
4.13 
7.93 
4.58 
5.26 
6.77 


Gallons. 


Per cent. 


1898 


627,980 
708,625 
983,360 
523,258 
612,711 
213,120 
1,022,980 
591,985 
668,385 


94.0 
108.0 
148.0 
78.5 
92.0 
38.0 
153.5 
89.0 
100.0 


1897 _ 


1898 _ 


1899 __ _ — - 


1900 , 


1901 


1902_ _.; _*_ 


1903 


1904 -- 


Average for 10 years 


6.44 


685,388 


100'. 


Normal for 16 years 


9.35 













a It should he noted that the statistics of exports do not discriminate between oil pro- 
duced hy the crop of the preceding autumn and that of two years previous, some part of 
which is sometimes held in reserve at Sfax if the market be dull. However, a com- 
parison of the average prices of olive oil at Marseille with the volume of the annual 
exports from Sfax furnishes no evidence that the price is the chief factor in determining 
the quantity exported each year. It is also uncertain to what extent the coming into 
hearing of the recently planted orchards may affect the figures, although presumably the 
addition thus made to the total production has been a gradual one and not likely to cause 
marked fluctuations. In the main, therefore, it is believed that the above figures are 
fairly representative of the annual crop. To arrive at the total annual production of oil 
by the Sfax orchards we must add to the figures in the column showing quantity pro- 
duced, 531,700 gallons, representing the average amount that is consumed locally or 
shipped overland to other parts of northern Africa. This is said to vary little from year 
to year. 

Although the records do not cover a sufficiently long period to 
establish a definite relation, it would appear that there is some con- 
nection between the size of the crop and the amount of rainfall of the 



13 
12 
II 
10 
9 
8 
7 
6 
5 
A 
3 


























1,100,000 
1,000,000 
900,000 
800,000 
700,000 
600,000 
500,000 
400,000 
300,000 
200,000 
100,000 






/ 


\ 






















/ 


\ ; 

\ / 
\ / 






















y 


\ / 




















1 

i 




/ \ 
f \ 














/ 

/ 






r 

1— 




\ 
\ 














/ 






i 




v- 

\ 
\ 






V / 
\ / 
\ / 


^ / 

\l 






/ ^ 

/ 

t 






— / — 
/ 

— / — 




V 






\ 1 


A 




— *c , 








/ 

-t 






N 




/ \ 
/ \ 


/v 




s 








/ 

4 










1 \ 

/ 

/ 














/ 














































1895 '96 '97 '98 '99 1900 '01 '02 '03 '04 1905 



Fig. 10. — Chart showing the rainfall in inches (dotted line) and the production of olive 
oil (solid line) at Sfax from 1895 to 1905, the oil production being expressed in num- 
ber of gallons exported during each following year. 



preceding year or years, but not that of the spring preceding the 
ripening of the crop. Thus, the comparatively heavy rainfall (3.6 



125 



34 



DRY-LAND OLIVE CULTURE IN NORTHERN AERICA. 



inches above the normal) in 1897 doubtless had something to do with 
the large crop of 1898, although the total rainfall of the first five 
months of the latter year was less than half of the normal. Again 
in 1901, when the crop was less than half the average of nine years, 
the rainfall for the first five months was not greatly below the 
normal, but that of the year previous was less than half the normal, 
and during the three years previous the annual rainfall was only a 
little more than half the normal. It is noteworthy that in 1900, 
after two years of rainfall much below the normal, the crop was 
about an average one. This was probably due to the heavy rainfall 
of Xovember, 1899, which was more than three times the normal 
for that month, while the precipitation during the first five months 
of the year in which the crop was made was less than 40 per cent 
of the normals 

That successful olive culture without irrigation is possible with 
even a smaller rainfall than the normal for Sfax is indicated by the 
fact that the oil production of 1903 was only a little below, and 
that of 1904 was slightly above, the average, although following 
periods of five and six years, respectively, during which the total 
annual rainfall was only about 60 per cent of the normal. 6 

LABOR. 

While some of the French owners of olive orchards near Sfax 
manage their own plantations directly or through foremen, the 
majority have found it more convenient, and until very recently 
more economical, to follow the practice of the native proprietors 
and enter into contracts with tenants, or " m'rharcis." The latter 
are natives more or less skilled in olive culture who undertake the 
planting and care of the trees. It was formerly customary to ter- 
minate the agreement between the proprietor and the m'rharci when 
all gaps in the orchard had been filled by replanting, all Bermuda 
grass had been extirpated, and the trees were beginning to bear, 
which was generally accomplished eight years after the planting. 
It is now more usual to continue the agreement until the trees begin 

a After this bulletin was in type, a report was received that the total exports 
of olive oil from Sfax in 1906 (crop of 1905) amounted to 592,000 gallons, which 
was below the average for the preceding ten years. Tbis is doubtless to bo 
explained by the small rainfall of the years 1902 to 1904, wbicb averaged only 
about 60 per cent of the normal. On the other hand, tbe total rainfall in 1905 
was 9.9 inches. 

h This may have been partly due, however, to the rapid extension of the 
orchards during tbe past twenty years having begun to make itself felt through 
the increase in the number of bearing trees. It is to be regretted that no data 
are available which would throw light on the influence of this factor as com- 
pared with that of annual variations in the rainfall. 
125 



LABOR IN OLIVE ORCHARDS. 



35 



to bear sufficiently to pay the current expenses of the orchard, i. e., 
for about ten years. At the expiration of the contract the m'rharci 
receives in remuneration for his services one-half of the area planted. 
This arrangement has the advantage of retaining in the neighbor- 
hood a number of skilled laborers upon whom the proprietor can 
generally depend for the care of his part of the trees after the con- 
tract has terminated. 

The division of the trees between the proprietor and the m'rharci 
is made by drawing lots, under the supervision of the amins, who act 
as agricultural magistrates, and whose duty it is to settle disputes 
between employers and employees. It is said that the amins, al- 
though themselves always natives, are generally fairly impartial in 
regulating differences between Europeans and their m'rharcis. The 
proprietor generally seeks to have the plantation divided in such a 
way that the holdings of his former tenants will be scattered among 
his own. Many of the m'rharcis prefer, however, to receive money 
for their share of the trees. 

At the beginning of the contract a sum amounting generally to 
30 or 40 cents for each tree is advanced by the proprietor, to be used 
by the m'rharci in purchasing the necessary animals, tools, etc. The 
loan, which bears no interest, is repaid when the agreement ends, 
usually in trees from the m'rharci's share. The proprietor furnishes 
the land, while the m'rharci contributes the truncheons that are 
planted, the tools and animals used, and all the labor required in 
clearing, planting, and cultivating. A single m'rharci generally 
plants and cares for from 150 to 300 trees, while if he has a family to 
aid him he can sometimes handle as many as 600. He requires one 
camel for plowing and cultivating every 25 acres. The entire product 
of the field crops grown in the orchard during the first few years is 
the property of the m'rharci, unless, as often happens, the proprietor 
furnishes one-third of the seed used, in which case he is entitled to 
from one- fourth to one- third of the crop. It is estimated 6 that under 
this system it costs about $1.40 per tree to set out an olive orchard and 
care for it until it is 10 years old. 

Until recent years, decidedly better results were obtained under the 
contract s}^stem above described than when the proprietor directly- or 
through a European foreman undertook to establish an orchard ; but 
the former method is becoming every year more expensive. Many 
of the best native growers now have trees of their own to care for 
and are no longer willing to bind themselves out as m'rharcis. The 
m'rharci no longer finds on the land to be planted an abundance of 
old trees from which truncheons can be obtained, and these must 

a See Bui. 92, Bureau of Plant Industry, p. 32. 

b Minangoin, N. L'Olivier en Tunisie, Tunis, 1901, pp. 59 and 68. 

125 



36 DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 

frequently be purchased for him by his employer. Furthermore, the 
m'rharei now expects his employer to advance him 40 cents or more 
instead of 20 to 30 cents per tree at the beginning of the contract. 

But, notwithstanding the increasing expense, the contract system 
still has decided advantages. Europeans who have planted and cared 
for orchards by hiring laborers under their direct supervision rather 
than by contracting with a m'rharei have generally found their ex- 
penses heavier and the work — especially that of getting rid of weeds — 
less efficiently done. Besides, they lose the advantage of having 
around them, when their trees begin to bear, a number of their former 
m'rharcis, skilled and trustworthy men with whom they have been 
accustomed to deal and who are usually willing, for moderate wages, 
to continue the cultivation of their old employer's orchard as well 
as of their own. 

Some of the large plantations belonging to nonresident Europeans 
are managed by a French agent or foreman under contract for a cer- 
tain period (generally ten years). He receives a small salary ($30 or 
$40 a month) and is entitled, at the expiration of his contract, to a 
certain percentage — usually one-eighth or one-tenth — of the land 
planted in olives. He in turn either hires laborers or else contracts 
with native tenants or m'rharcis for the planting and cultivation of 
the orchard. It is said that an orchard established under the super- 
vision of a competent foreman will yield sufficient fruit after eight 
years to pay all or most of the running expenses. 

The cultivation of the orchard after the m'rharei contract has ex- 
pired is carried on either by reengaging the m'rharei, in which case 
he receives one-third or one-half of the crop produced, or else by 
hiring day laborers. In the latter case it usually costs the owner 18 
cents per tree annually to have the cultivation and pruning done. 
If paid by the day, a laborer earns from 40 to 50 cents when engaged 
in cultivating or plowing. With a camel he can plow 2|- acres in 
two or three days and can cultivate the same area with a " maacha "' 
in one day. For pruning, which requires special skill, a man re- 
ceives about 60 cents a day. The crop, as we have seen, is generally 
gathered under contract by the purchaser, the harvesters being 
usually paid with a share of the fruit. 

UTILIZATION OF THE RUN-OFF IN OLIVE CULTURE IN OTHER 

PARTS OF TUNIS. 

Olive orchards occupy large areas in northern Tunis, notably 
in the neighborhood of the capital itself and in the valley of the 
Mejerda, the principal river of Tunis. In this region the annual 
rainfall a is sufficient for olive production without any special meas- 



a The average annual rainfall at the city of Tunis is 18.S inches. 
125 



RUN-OFF IN OLIVE CULTURE. 



37 



ures being taken to conserve the soil moisture. The olive is also an 
important tree in some of the oases of southern Tunis, where the 
scantiness of the rainfall a is compensated for by the abundant supply 
of water from springs that is available for irrigation. 

But in one of the most important olive-producing regions in 
Tunis, i. e., that surrounding Susa h on the eastern coast, the normal 
annual rainfall of 16.6 inches, although greatly exceeding that at 
Sfax, is yet so small as to make it worth while to employ a special 
method for utilizing it to the fullest possible extent. This method 
is very different from that used at Sfax, and in its way is almost 
equally interesting. The country around Susa is very hilly, being 
divided by limestone ridges into small valleys and ravines. The 
bottoms of these valleys and the lower slopes, which are made suf- 
ficiently level for the purpose by a system of terracing, are occupied 
by small basins, separated one from another by low banks of earth. 
Each basin contains a few olive trees, usually only from two to eight. 
The stony upper slopes and summits of the ridges, which produce a 
scanty natural growth of shrubs and grasses, are not cultivated. At 
intervals along these slopes, or " meskas," as they are termed by the 
Arabs, are shallow trenches running obliquely toward the bottom. 
These are so arranged as to catch and conduct to the basins as much 
as possible of the rain water that falls upon the slope. The owner 
of each orchard has a recognized right to all water that falls upon 
the slopes adjacent to his property. The basins are said often to 
remain filled with water during the month of January. 

The heavier texture of the soil around Susa as compared with that 
at Sfax is favorable to this method of irrigation by rainfall, as it 
permits the water to flow from basin to basin, instead of being all 
quickly absorbed in the first one. It is generally observed in this 
region that olive orchards that are watered by the rain that falls on 
the " meskas " give larger and especially more regular yields than 
those receiving only direct rainfall. 

From the nature of the case, accurate alignment and widely dis- 
tant planting of the trees as practiced at Sfax are out of the question 
at Susa. The trees stand comparatively close together, so that there 
are often forty to the acre instead of only seven to ten, as at Sfax. 
Much less care is taken to cultivate the soil, and this also is more or 

a The normal annual rainfall in the oasis of Gafsa is S.5 inches ; in that of 
Gabes, 7.6 inches ; in that of Tozer, 5.1 inches. In the oasis of El Oudiane, 9 
miles distant from Tozer (see Bulletin 02, Bureau of Plant Industry, p. 16), 
there are 25,000 olive trees, with an average yearly production of 132,000 gallons 
of oil. 

6 Susa, better known by its French name of Sousse, is about 70 miles south- 
east of Tunis and about an equal distance north of Sfax. 
125 



38 



DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



less inevitable from the nature of the ground; but there seems to be 
no good excuse for the small attention that is paid at Susa to prun- 
ing, as compared with the thoroughly scientific way in which this 
operation is performed in the Sfax orchards. 

Many of the trees have several trunks, which is explained by the 
natives as having been due to a violent storm, which a century ago 
laid low most of the olive trees around Susa, after which event 
several shoots at the base of each tree were allowed to spring up. a 
The greater part of the olive trees around Susa are of great age, 
often 100 or 150 years old, it is said. But when well cared for with 
respect to cultivation of the soil, pruning, and manuring, even these 
old trees are reported to give good returns, netting the owners in 
some years as much as 95 cents to the tree, or $38 per acre. & 

SUMMARY. 

(1) Arboriculture is an important phase of dry-land agriculture 
and one that has as yet received little attention in the United States. 

(2) The olive, owing to its peculiar leaf structure and to the char- 
acter of its root system, is especially fitted for growing in regions 
where the rainfall is slight and irrigation is impossible. 

(3) Fifteen hundred years ago the olive was grown without irriga- 
tion under a rainfall of from 8 to 14 inches over an extensive region 
in northern Africa, the prosperity of which in Roman times depended 
chiefly upon its production of olive oil. A vast region that is now 
practically an uninhabited desert was then covered with olive orchards 
and with flourishing cities and towns. 

(4) During the last hundred years much progress has been made 
in reestablishing dry-land olive culture in southern Tunis. There 
are now nearly 500,000 acres of unirrigated olive orchards in the 
neighborhood of Sfax. 

(5) As would be expected from its nearness to the Sahara, the cli- 
mate of Sfax is almost desert-like. The summers are very hot and 
the average annual rainfall is only 9.3 inches, sometimes falling below 
an average of 6 inches for seven consecutive years. As in California, 
the summer is the dry season and the winter the wet season. 

(6) The ground water lies too deep to be reached by the roots of 
the trees. No water is available for irrigation. 

(7) The soil of the Sfax region that is considered best adapted to 
olive culture is a red loam or fine sandy loam that is fairly uniform 
in texture to an average depth of seven feet. It is very retentive of 
moisture, rich in lime and potash, but apparently deficient in nitro- 
gen and phosphoric acid. 

a Minangoin, X. L'Olivier en Tnnisie, Tunis, 1901, p. 32. 
& Minangoin, N., 1. c, p. 54. 

125 



SUMMARY. 



39 



(8) Only one variety of olive, the Chemlaly, a small-fruited oil- 
producing variety, is extensively grown in the Sfax region. It is a 
very productive variety and its fruits yield an unusually high per- 
centage of oil. 

(9) Wide planting and thorough cultivation are the most impor- 
tant principles of olive culture at Sfax. The trees are planted 65 to 
80 feet apart in each direction, giving space for only seven to ten 
trees to the acre. 

(10) The olive is propagated at Sfax by means of large truncheons 
or pieces of old wood; each containing several buds. These are set 
to a depth of about a foot in holes, which become gradually filled as 
the young trees grow up. During the first summer or two, two or 
three waterings by hand are usually given. All shoots but the best 
one are trimmed away within three years after setting out the 
truncheon. 

(11) A good dust mulch is always maintained on the surface of 
the orchard, and weeds, of which Bermuda grass is the most trouble- 
some, are kept down by frequent cultivation. As a rule, the soil is 
stirred by a shallow plowing three times a year. The most impor- 
tant plowing is the one that immediately follows the harvest. After 
the trees begin to bear, no other crop is allowed to grow among them. 

(12) Great care is taken in the matter of pruning, the trees being 
given a broad, symmetrical top. The interior branches are thinned 
out so that plenty of light and air can reach all the fruit-bearing 
twigs. The comparatively sterile, rapidly growing, erect branches 
are removed. Skillful pruning is an important factor in the large 
yields obtained. 

(13) The harvesting is done by hand, more than usual care being 
taken to avoid bruising the fruit or breaking the branches. 

(14) After eight or ten years the trees generally yield enough 
fruit to pay the current expenses of the orchard, and when about 25 
years old they are in full bearing. The average yield per tree is then 
about 24 gallons of fruit, which gives 6 gallons of oil. 

(15) There is apparently a relation between the yield of the olive 
and the rainfall of the previous year, but none between the yield and 
the rainfall of the year in which the crop is made. 

(16) In another part of Tunis, where the rainfall is about 16.5 
inches and the country more hilly than around Sfax, the rain that 
falls on the slopes is collected in trenches and conducted into small 
basins in which the trees are planted. 

125 



PLATES. 



125 



41 



DESCRIPTION OF PLATES. 

Plate I. Frontispiece. Harvesting Cheinlaly olives in a dry-land orchard at 
Sfax in southern Tunis. Since the quality of the oil is impaired if the 
fruit becomes bruised, the use of a pole is avoided and the picker uses a 
ladder to reach the fruit-bearing twigs. Pruning is managed so that every 
part of the tree can be reached in this way. The native pickers protect 
their fingers with the tips of rams' horns and can thus strip the fruit off 
the twigs without injuring their hands. The olives are collected in the 
large baskets shown in the illustration and are transported by camels to 
the factory. The plate also shows the clean cultivation of the orchards, 
the dust mulch maintained on the surface, and the care with which pruning 
is done. 

Plate II. General view of the older dry-land olive orchards near Sfax, showing 
the wide planting and clean cultivation practiced and the uniform shape 
given the trees by careful pruning. The leafless trees in the foreground 
are figs, these and other fruit trees being occasionally planted in the olive 
orchards that belong to natives. (From a photograph furnished by the 
Direction des Antiquites et Beaux Arts at Tunis.) 

Plate III. A fruit-bearing twig of the Chemlaly olive, natural size, from a pho- 
tograph by M. Minangoin. The fruits of this variety are small but numer- 
ous and are very rich in oil. They are jet black when ripe. 

Plate IV, Fig. 1. — Recently planted dry-land olive orchards about twenty miles 
from Sfax. The view shows the careful alignment and wide spacing of the 
trees, which are 80 feet apart each way and number only 7 to the acre. 
Most of the trees shown are from ten to twelve years old. The hillside 
in the immediate foreground and that in the left background are unfit for 
planting to olives because of the absence of soil, a calcareous rock coming 
to the surface at these points. Fig. 2. — The interior of an older olive 
orchard at Sfax, showing the entire absence of weeds, the great distance 
between the trees, and the well-rounded symmetrical form of the trees 
due to scientific pruning. These trees are about thirty years old and are 
in full bearing. 
125 
42 



Bui. 125, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



Plate II. 




Bui. 1 25, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



Plate III. 




A Fruit-Bearing Twig of the Chemlaly Olive. 

(Natural size.) 



Bui. 125, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



Plate IV. 




Fig. 2.— The Interior of a Sfax Olive Orchard, Showing Wide Planting, Clean 
Cultivation, and Careful Pruning. 



INDEX. 



Page. 

Africa, ancient, importance of dry-land arboriculture S-12 

Agriculture, dry-land, importance of arboriculture 38" 

Algeria, ancient, flourishing condition, causes, etc 10-12 

population 9 

condition from third to seventh century 0-12 

Almond, cultivation in ancient Tunis 11 

orchards, establishment by French capitalists , 13 

Amins, Sfax, duties in settling contracts 35 

Amphitheater of Thysdrus 10 

Arabs, destruction of olive orchards in ancient Tunis 12 

Arboriculture, importance in ancient Africa 8-12 

Arizona, Tucson, precipitation compared with Sfax 15 

temperature changes compared with Sfax 15 

Barley growing in olive orchards 27 

Basin, olive tree, purposes 26-27 

Basins, olive orchards, use in conservation of moisture 39 

Beans, horse, growing in olive orchards 27 

Bermuda grass. See Grass, Bermuda. 

Bertainchand, opinion on cause of excess of stearin in Sfax olives 20 

Calcium carbonate. See Lime. 

California, Fresno, precipitation compared with Sfax 15 

San Diego, precipitation compared with Sfax 15 

Camels, use in cultivation of olive orchards, Sfax 35 

marketing olives, Sfax 30-31 

Chemlaly olive, oil content 19 

quality 19 

sale in European countries 19 

tree, description 19-20 

Christ thorn, habits 17 

Sfax, resemblance to mesquite of New Mexico 17 

Cisterns, ancient Tunis, remains 10 

Sfax, description, use, etc 16 

Clay content, soils of Sfax region 18 

Clearing land for olive planting 21-22 

Sfax region, difficulties from Christ thorn 17 

Contract system, olive orchards, Sfax 34-36 

advantages 36 

increase of expense 35 

Contracts, care of olive orchards, Sfax, advance payments , 35 

olive orchard planting and care, Sfax 34-36 

Cottonwood, propagation in Kansas from " snags " 20 

Crops, field, grown in olive orchards, Sfax, ownership 35 

125 43 



44 



DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



Tage. 

Cuttings, olive, imported, from Sfax by Agricultural Department, 1905, 

history, etc 21 

securing, care, etc 21 

See also Truncheons. 
Drappier, Louis, recommendation of use of cactus pads in planting 

olive truncheons 24 

Dry-land agriculture, importance of arboriculture 38 

in ancient Africa 8-12 

olive culture in modern Tunis 12-30 

tree culture, relation to wealth of ancient Tunis 11 

seasons, effect on yield of olives 34 

"Dust mulch, olive orchards, necessity 25. 39 

El Oudiane, oasis, olive production 37 

Exports of olive oil from Sfax, 1S05-1904 33 

1906 34 

Factory, olive oil, treatment of fruit before pressing 31 

Fertilizers, chemical, not used in Sfax olive orchards , 28 

Fig, cultivation in ancient Tunis 11 

Foreman, olive orchards, Sfax, requirements 36 

France, Provence, olive trees, production of oil compared to Sfax trees 32 

Fruit, value of olive trees 20 years old at Sfax 32 

yield at different ages of olive tree, average 31-32 

Gabes, oasis, annual rainfall 37 

Gafsa, oasis, annual rainfall 37 

Grain crops in olive orchards 27 

Grass, Bermuda, extirpation, methods at Sfax . 25-27 

troublesome weed in Sfax region 22 

Harvest time, olives, at Sfax 30 

Harvesting, olive, gathering by hand 30 

method at Sfax 30-31, 39 

Holes for planting olive trees, number dug per day by one laborer 23 

Horse beans, growing in olive orchard 27 

Introduction to bulletin 7-8 

Irrigation, ancient Tunis, not practicable 10 

Italy, Bari district, oil content of olives 19 

" Kaffiz," measure for selling olives, size, etc 31 

Labor, olive growing, cost by day at Sfax 24 

management at Sfax 34 

remuneration at Sfax 35 

requirements of mrharcis at Sfax 35 

Ladder, use in olive harvesting 30 

Lands, Tunis, purchase from government, rates, conditions, etc 13 

Lime content, soils of Sfax region IS 

Limestone regions, suitability for olive culture 19 

" Maacha," use by Arabs in eradication of Bermuda grass from olive 

orchards 25 

Manure, barnyard, application to olive trees, method 2S 

use in olive orchards 28 

Marketing, olive, variation in prices at Sfax 31 

" Meskas," Susa region 37 

Mesquite, New Mexico, resemblance to Christ thorn of Sfax 17 

" Messaba," use in gathering rootstocks of Bermuda grass at Sfax 25 

125 



INDEX. 



45 



rage. 

Mills, olive oil, Sfax, number, equipment, etc 32 

Minangoin, N., number of wells to given orchard recommended 24 

recommendation for extirpation of Bermuda grass 25 

table showing average yield of olives and oil per tree 

at Sfax : 31 

Moisture, conservation in olive orchards, methods in Susa region 37 

suggestion of French tenant ■ 27 

Tunis 39 

use of basins and trenches 2G-27 

" M'rharci " contract, relation of Bermuda grass 26 

" M'rharcis," contracts for planting olive orchards, conditions, Sfax 34 

remuneration for ten years' care of orchard 35 

Mulch, dust, necessity in Sfax olive orchards 25, 39 

New Mexico, eastern, topography compared with Sfax region 17 

Nitrogen content, soils of Sfax region IS 

Oases, southern Tunis, olive culture 37 

Oil conduit, ancient Tunis 12 

content of Chemlaly olive 19 

olive in Europe at northern limit of production 19 

influence of climate 19 

mills, ancient Tunis, construction 11 

ruins in Tunis 11 

Sfax, numbers, equipment, control, etc 13, 32 

olive, exports from Sfax, 1895-1906 33 

1906 34 

from oases of Sahara Desert, resemblance to that of northern 

Tunis, cause 20 

percentage of weight of fruit and average yield at different 

ages of tree 31-32 

produced in limestone regions, quality 19 

supply of ancient Rome from Tunis 11 

trade, southern Tunis, decline, causes 12 

yearly production of southern Tunis 13 

Olive, Chemlaly, adaptability to hot, dry climate 20 

culture, adaptation to dry regions 3S 

ancient Africa 38 

congress held at Tunis, 1888, decision as to orchards and 

yield of Tunis orchards , 13 

introduction of present sytem 12 

methods of dry-culture in Tunis 14 

northern Tunis 36-38 

southern Tunis, revival 3S 

Susa region, methods 37-38 

without irrigation, possibilities of dry climates 34 

orchard. See Orchard, olive. 

production, yearly, Sfax, 1895-1904 33 

1906 34 

tree, age for bearing 24 

trees aged, in Tunis 11 

Chemlaly, causes of large yield at Sfax 20 

number planted, 1892-1904 13 

variety grown in Sfax region 39 

Olives, marketing, variation in prices, etc 31 

pickling varieties, need of abundant water 20 

prices 31 

125 



46 



DRY-LAND OLIVE CULTURE IN NORTHERN AERICA. 



Page. 

Olives, propagation, methods at Sfax 20-21 

sale on tree, custom 30 

time of ripening 30 

Orchards, olive, Algeria, use of cactus pads by Arabs in planting 24 

ancient Tunis, destruction by Arabs 12 

extent 11 

conservation of moisture, methods at Sfax 25-2S 

cultivation 27 

distance between trees 22 

establishing, steps 21-27 

necessity for clean culture 26 

propagation, planting, etc 19-36 

Provence, France 32 

restoration in Tunis, encouragement by government 13 

Sfax 19-36 

age at which trees pay expenses 36 

appearance and yield 13 

clearing the land 21-22 

cultivation after expiration of contract, manage- 
ment, expenses, etc 35 

extent, 1881 12 

growth since 1881 13 

harvesting 30-31 

labor 34-36 

manuring 2S 

planting 22-24 

propagation 20-21 

proprietors, requirements by m'rcharcis' contract 35 

pruning 28-30 

relation of rainfall to yields 32-34 

tillage 25-27 

variety grown 19-20 

work of French capitalists 12-14 

yields 31-32 

southern Tunis, present extent 13 

Panniers, use in marketing olives 30 

Phosphoric acid content, soils of Sfax region __ IS 

Pistache, cultivation in ancient Tunis 11 

Planting, olive, time and method 23 

methods at Sfax 22-28 

Plates, description 42 

Plowing, deep, clearing land for olive orchards 22 

methods for extirpation of Bermuda grass in olive orchards 25 

olive orchards 26 

Pole, use in harvesting, injury to fruit and trees 30 

Populus deltoides. Sec Cottonwood. 

Potash content of soils of Sfax region IS 

Precipitation, El Paso, Tex., compared with Sfax 15 

Fresno, Cal., compared with Sfax 15 

relation to olive yield 32-34,39 

St. George, Utah, compared with Sfax 15 

San Antonio, Tex., compared with Sfax 15 

San Diego, Cal., compared with Sfax 15 

125 

\ 

I 

LEJa'i 



INDEX. 



47 



Page. 

Precipitation, Sfax, annual , 15-16, 33 

variation for different years 16 

Tucson, Ariz., compared with Sfax 15 

Tunis 8 

Presses, olive oil, steam and animal traction, numbers at Sfax 32 

Prices of olive trees at different ages 31 

olives at factory 31 

Propagation of olive at Sfax, methods 20-21 

use of truncheons at Sfax 39 

Priming olive trees, annual, Sfax 20-30 

biennial, time, etc 20 

cost by the day 36 

relation of method to harvesting 30 

Sfax, cost 28 

methods 27-30, 30 

Susa region 38 

Rainfall. See Precipitation. 

Ripening, olive : 30 

Root shoots, olive tree, priming 28 

system, olive tree 10, 22 

Run-off, utilization in olive culture in Tunis 38 

Sagebrush, Sfax 17 

Sahara Desert, olive oil of oases, resemblance to that of northern Tunis, 

causes 20 

Sand content of soils of Sfax region 18 

Sea water, use in Sfax 16 

Sfax, climate 14,15-16,38 

olive orchards 10-36 

precipitation, annual average 15-16 

variation for different years 16 

region, characteristics 14-10 

climate, description 14-17, 38 

reestablishment of olive culture 12-14 

temperature, average monthly 14 

topography, vegetation, soils, etc 17-10 

Shoots, olive truncheons, management 23 

Silt content of soils of Sfax region 18 

Soils, olive culture, high lime content necessary 19 

Sfax region IS 

chemical analyses, results 18-19 

description 17-19, 3S 

mechanical analyses, results 18 

water content 17-18 

Susa region, compared to Sfax region 37 

Stearin content, Chemlaly olive oil 19, 20 

high content in olive oil, causes 20 

Suffetula, flourishing condition, third to seventh century 10 

Summary of bulletin 38-30 

Susa, annual rainfall 37 

region, topography 37 

situation 37 

125 



48 DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



Page. 

Temperature, monthly mean, Sfax 14 

olive culture, importance 15 

Texas, El Paso, precipitation compared with Sfax 15 

San Antonio, precipitation compared with Sfax '_ 15 

temperature changes compared with Sfax 15 

western, topography compared with Sfax region 17 

Tillage, olive orchards, Sfax 25-28 

Topography of Sfax region 17 

Tozer, oasis, annual rainfall 37 

Trabut, Dr. L., suggestion for use of Chemlaly olive as stock for larger 

fruit I 20 

Trees, olive, age for maximum yield 32 

pruning 28 

bearing age, differences, causes 31 

cost, first ten years : 35 

of planting 24 

full bearing age, yield, etc 39 

method of planting 13 

old, disappearance, Sfax 35 

treatment to bring into bearing : 32 

periodic bearing, characteristics 32 

prices for different ages 31 

pruning, methods at Sfax 28 

Susa region, peculiarities of form 38 

Truncheons, olive, management 20, 24 

planting in nursery form 24 

use in propagation of olives 39 

See also Cuttings. 

Tunis, climate not changed since ancient times 10 

northern, olive culture 36-38 

uninterrupted 12 

present condition 8-9 

Twigs, olive tree, injury by use of pole in harvesting 30 

Vegetation, natural, Sfax region 17 

Water, absence of perennial streams in Sfax region 16 

scarcity, Sfax region 38 

sea, use in Sfax 16 

selling in Sfax_ 16 

Watering olive trees, methods at Sfax__* 24 

young trees, necessity, methods at Sfax, etc 24 

Wells, number required for given orchard 24 

Sfax, description 16 

Wheat growing in olive orchard 27 

Wood, scarcity and need at Sfax 28 

Yields, average, of fruit and oil of olive trees at different ages, Sfax 31-32 

Zizyphus spina-christa. See Christ thorn. 
125 

o 



a '09 



I 

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■ 

t 



